Experimental Toxoplasmosis in Rats Induced Orally with Eleven Strains of Toxoplasma gondii of Seven Genotypes: Tissue Tropism, Tissue Cyst Size, Neural Lesions, Tissue Cyst Rupture without Reactivation, and Ocular Lesions.
Experimental Toxoplasmosis in Rats Induced Orally with Eleven Strains of Toxoplasma gondii of Seven Genotypes: Tissue Tropism, Tissue Cyst Size, Neural Lesions, Tissue Cyst Rupture without Reactivation, and Ocular Lesions.
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DOI：
10.1371/journal.pone.0156255
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发表时间：
2016
期刊：
影响因子：
3.7
通讯作者：
McConkey GA
中科院分区：
文献类型：
--
作者：
Dubey JP;Ferreira LR;Alsaad M;Verma SK;Alves DA;Holland GN;McConkey GA
弓形虫是原生动物寄生虫中分布最广、最成功的寄生虫之一。弓形虫改变了啮齿动物的行为，使受感染的啮齿动物改变了对猫气味的恐惧，确实被猫的尿液吸引而不是排斥。寄生虫在大脑中的位置可能会影响这种行为。然而，大多数研究都是基于高度敏感的啮齿动物--老鼠。在相同年龄、品系和性别的大鼠(每株弓形虫10只)口服感染7种基因的11株弓形虫卵囊(自然途径和自然感染阶段)后，诱发了潜伏的弓形虫感染。于接种后2个月处死大鼠(P.I.)调查寄生虫基因是否影响分布、位置、组织囊大小或病变。组织囊在大脑的不同区域被计数，无论是在组织切片中还是在生理盐水匀浆中。脑部各区域均可见组织囊变。大鼠不同脑区的组织囊密度差异很大，有的动物多个区域高度感染。总体而言，丘脑感染最严重，尽管有大量的变异性。大脑皮层、丘脑和小脑的组织囊密度较高，两个菌株表现出对丘脑和嗅球的趋向性。组织学上，损伤仅限于大脑和眼睛。组织囊肿破裂是常见的，没有明确的证据表明速殖子重新激活。术后2个月，92只大鼠眼内有23只眼(25%)出现眼部病变。主要病变是视网膜的局灶性炎症。1只大鼠巩膜内可见组织囊肿，2只大鼠视神经内可见组织囊肿。脉络膜未受影响。只检测到组织囊肿，而不是活动性速殖子感染。20只大鼠舌组织切片中可见组织囊，而心肌和腿肌中未见组织囊肿。这项研究对弓形虫病的大鼠模型进行了深入的评估，可视化了包囊破裂，并阐明了寄生虫生物学的许多方面，对未来的研究有用。
The protozoan parasite Toxoplasma gondii is one of the most widely distributed and successful parasites. Toxoplasma gondii alters rodent behavior such that infected rodents reverse their fear of cat odor, and indeed are attracted rather than repelled by feline urine. The location of the parasite encysted in the brain may influence this behavior. However, most studies are based on the highly susceptible rodent, the mouse. Latent toxoplasmosis was induced in rats (10 rats per T. gondii strains) of the same age, strain, and sex, after oral inoculation with oocysts (natural route and natural stage of infection) of 11 T. gondii strains of seven genotypes. Rats were euthanized at two months post inoculation (p.i.) to investigate whether the parasite genotype affects the distribution, location, tissue cyst size, or lesions. Tissue cysts were enumerated in different regions of the brains, both in histological sections as well in saline homogenates. Tissue cysts were found in all regions of the brain. The tissue cyst density in different brain regions varied extensively between rats with many regions highly infected in some animals. Overall, the colliculus was most highly infected although there was a large amount of variability. The cerebral cortex, thalamus, and cerebellum had higher tissue cyst densities and two strains exhibited tropism for the colliculus and olfactory bulb. Histologically, lesions were confined to the brain and eyes. Tissue cyst rupture was frequent with no clear evidence for reactivation of tachyzoites. Ocular lesions were found in 23 (25%) of 92 rat eyes at two months p.i. The predominant lesion was focal inflammation in the retina. Tissue cysts were seen in the sclera of one and in the optic nerve of two rats. The choroid was not affected. Only tissue cysts, not active tachyzoite infections, were detected. Tissue cysts were seen in histological sections of tongue of 20 rats but not in myocardium and leg muscle. This study reevaluated in depth the rat model of toxoplasmosis visualizing cyst rupture and clarified many aspects of the biology of the parasite useful for future investigations.